Electrodeposition of nickel



Patented Nov. 10,

Harsh .W Chemical Company, Cleveland, @Qhio',

cor iora'tioniof o m mowing, Application March 6, 1952, Serial No.275,220

is meat.

This invention relates to v eleg:trodeposition v of bright ,nickel bythe use of a single brightenin s ticn nt 9 th bis-.p iqinmm FY9319?mixture of equivalent addition agents of the same y is t l...

t h ,i r s et in n i n. it ha v ber posed to use compounds of theaboveiclassas brighteners in connection with auxiliary brighteners foracid nickel plating from a -Watt's-type of solution. The maximumconcentration, however, was thought to be about five o'ne-hundredths ofa gram per liter ('five thousandths being considered hatter) inasmuch asgreater amounts were found to embrittle the deposit, and the auxiliarybrightener was thoughtjessential. I

I have now-disco'veredthat by using comparatively large concentrationsof such addition agents as the sole brightener an acid nickel platingsolution I am able to produce deposits which are indeed brittle, but thebrittleness-of whichis of a surprising and for many purposes unobjectionable type. When I first eiramined these deposits, which becausethey build brightness so rapidly may be called q'iiick bright nickel, Ithought them to be ductile without the usual aromatic sulfonat'e or sulfonarnid; They do not produce the characteristic fcry? -of the usual typeof brittle deposits upon sharp bending-n01 iS there evidence of crackingvisible to the naked eye. These deposits, as indicated, have theproperty of building brightness at -a remarkably fast rate, v so thatrelatively thin "deposits on unbuiied or mattesur faces exhibit extremebrilliance; and they are characterized byeXc'ellent smoothingandscr'atch filling. On the otherhand, microscopic-examinae tionindicates that these "dfipos'its ar *full of fine hair-line cracks notdiscernible 'by-the naked eye. Adherence to steel is not good, but a0.00017 :to 020002". copper deposit on steel prior to fquic k brightnickel prdti'des satisfactoryadherence Adherence to brass, copper andgray nickname trodeposits is satisfactory. c

Poor adherenceand visiblecracking of the deposit, whichcan be producedby too :high concentrations of addition agent, arerelated not only tosuch concentration but also to the thickness of the deposit, For thinflash coatings for quick brightness building a high conc ntrationofaddition agentmaybe used. For thickerdepositsjto avoid stresscracking, lower cbncenaa icas'are superior, Tests indicate t1'iatthe-appearance "of the deposit is not'alterd arte'r proi' geguse-or the"solution. Ga rb'on treatment =6: the semi-1pc after long use producesftl ie br'dinary grayaii eke lsolution. "The deposit'eitliibit'smieraseopittracrs at the start and, as far s has been determined,retains thisjproperty indefinitely.

In salt spray corrosion comparisons with 'a commercial bright nickeldeposit it was found that in the case of thin dep'osits (0.0001" to0.0002") directly on steel the commercial deposit was much superior tothe quick bright deposits of the same thickness. On copper deposits (0.4to 0-,8,m n st e ther wasn an re iable di t nc exc pt tha le s gre.discq q at sm e d w th the zcommercia n ck In a ll ie above cases thequick bright nickel is much br hie la d m qt ha h comm rcia T a s-h ickeriep s'it .;A Qit e c rms ion an s w r s ren im ac test w t iro' weight,and in most-cases it was round that nickel deposits according to theinvention were superior to the commercial f bright nickel around t mpa;acre:. i -v l.

C ns d r t ef ifl lt of la in bra s and particularly {copper directlywith chromium, it

would appear commercially desirable to use the novel deposits ,as laflash coating on copper or brass prior tochrome plating. A flash coatingi h qqra n lai idie s n gives n 1 cellent appearing finish. Heavierthicknessesmay be O apt c a rams u he es -hfi ries obtainable in thincoatings would ,appear to be 0f mo e mercia1 inte est hin-coatings c thenovel bright nickel over gray or semi-bright nickel have the advantageof improving thelustre although without improving the resistance tocorrosion. I

It is ph iqu th 'ith ishtnick l cc ain tqqtne nt on can be us d effe t eu de lci i stances wh re xt eme bri htnss is desi e 1- pecia l Wh r it ides r d .t l lii d. v11 s,1, tnJ ss quic l t is m nis th eastpo vsihle.gq'u ti r f ck l: iASi H l LKnQ h+flldbri t QPQQ i .ln i k l y as brighas com rc bright nickelz It'does, "however, m a ry excellent surfaceqnlwhichtp epos n cke mat qc rd n t err g i in Emma, the icke dep i ltit 1 1 lbr elitngS when ittle a /mes pr v des a lamin tedg a g od c os nr is a c. are adhs' ,7 is brilliant n'ckel color (due *to 'brighteninjgSmoothing c lnwh'ile(b in econ deposits according to the present inve H59 s arc ed v'srrrarnicke,snares l. inl sl' froni "the '-Watts bath, orover senii=bright 'riickel' nickel such as obtained from a Watts bathmodified by the addition of coumarin. Still other applications of theinvention may be found feasible and advantageous.

The preferred basic solutions in connection with which the invention isrealized are as follows:

TABLE I All sulfate NiS .7H O 100 to 400, preferably 200 to 300 gramsBoric acid 0 to 60, preferably 10.to 40 grams H 0 to make 1000 cc.

High chloride NiSO4.6H20 7 to 225, preferably 190 to 200 grams NiCl fiHO 50 to 150, preferably 70 to 1o0 grams Boric acid O to 60, preferablyto 40 grams H20 to make 1000 cc.

Sulfate-chloride (Watts type) N,N'- (oxydibutyl) -bis-pyridiniumchloride N,N- (oxydibutyl) -bis-isoquinolinium chloride N,N'-(2-butenylene) -bispyridinium bromide N,N- (Z-butenylene)bis-isoquinolinium bromide The last compound has the followingstructure:

QC RGHFQ QECHHGQ3 The bromides and chlorides are fully equivalent toeach other. No anti-pit agent is used, since no substantial pittingoccurs.

These compounds are maintained in the acid nickel plating solution,preferably those above described, in concentration from 0.1 to 1.0 gramper liter, preferably from 0.2 to 0.75 gram per liter.

'NiS0 ..7H '0 100 to 400, preferably 200 to 300 grams NiCl .6H O 10 to60, preferably 25 to 40 grams Boric acid 0 to 50, preferably 15 to 40grams H 0 to make 1000 cc.

To each of the foregoing basic solutions I add one or a mixture ofcompounds of the formula:

shown by several examples in Table II below) containing in the aggregatefor both pyridinium groups from 1 to 10 carbon atoms, the extra valencesof the carbon atoms of A being satisfied by hydrogen and from 0 to 1hydrocarbon groups containing in the aggregate from 1 to 6 carbon atoms,and where each hydrocarbon substituent group is attached to from 1 to 2atoms of the group carrying such substituent group.

The following compounds are specific examples of the groups of additionagents above referred to, the same being utilized according to theinvention in acid nickel plating solutions, preferably nickel sulfateand mixed nickel sulfate and nickel chloride solutions, suitably thebasic solutions above set forth.

TABLE II N,N'-oxydiethylene pyridinium isoquinolinium chloride g 7Propanone-l,3-bis-pyridinium chloride N,N'-oxydipropylene-bis-pyridinium perchlorate The following specificexample will serve to illustrate the invention:

EXAMPLE I A solution was made up containing:

Grams NiSO4.6H2O 240 NiClzfiHzO 40 H2303 40 N,N-ethylene-bis-pyridiniumbromide 0.4 H20 to make one liter.

This solution was operated at a pH of 3.5, a temperature of F. and acathode current density of 40 amperes per square foot. On a matte coppersurface produced by electrodepositing copper on steel, extremebrilliance was achieved at a thickness of 0.000065 of an inch. On brightcopper produced by electrodeposition from a commercial ,bright coppersolution, extreme brilliance was achieved at a thickness of 0.00003 ofan inch. On a vapor blasted steel panel having a roughness of RMS 34.5,quick bright nickel was deposited to a thickness of 0.000? of an inch.The deposit exhibited an RMS of 6.6 and was fully bright.

On the bright copper above referred to, increasing the concentration ofthe addition agent to 0.75 gram per liter resulted in securing extremebrilliance at a thickness of 0000015 of an inch, while decreasing it to0.1 gram per liter resulted in securing extreme brilliance at 0.0005 ofan inch.

. Having thus described the invention, what is claimed is: l

1. A nickel plating solution comprising an aqueous, acid solution ofnickel material supplying nickel ions and an addition agent dissolved insaid solution and capable of imparting to electrodepositsproducedtherein improved rates of increasing brightness with respect toincreasing thickness of deposit, said solution consisting essentially ofa composition from the class consisting of. aqueous solutions of nickelsulfate and aqueous solutions of nickel sulfate and nickel chloride andsaid addition agentbeing atleast one bis-pyridiniumcompound of theformula,

where A is achain made up of from 1 to 10 carbon atoms and from 0 to2oxygen atom and the free valences are satisfied by hydrogen and from 0to 4 hydrocarbon groups containing in the aggregate for both pyridiniumgroups from 1 to 10 carbon atoms, the extrarvalencesof the carbon atomsof A being satisfied by hydrogen and from 0 to 1 hydrocarbon groupscontaining in the aggregate carbon substituent group is attached to from1 to 2 atoms of the group carrying such substituent roup, said additionagent being present in solution to the extent of from 0.1 to 1.0 gramper liter.

2. The invention as defined in claim 1 wherein the concentration of saidaddition agent is from 0.2 to 0.75 gram per liter.

3. The invention as defined in claim 1 wherein the addition agent is N,N'-ethylene-bis-pyridinium bromide.

4. The invention as defined in claim 1 wherein the addition agent isN,N-trimethylene-bispyridinium bromide.

5. The invention as defined in claim 1 wherein the addition agent isN,N-tetramethylenebispyridinium bromide.

6. The invention as defined in claim 1 wherein the addition agent isN,N'-pentamethylene-bispyridinium bromide.

'7. The invention as defined in claim 1 wherein the addition agent isN,N'-methylene-bis-pyridinium bromide.

8. A nickel plating solution comprising an aqueous, acid solution ofnickel material supplying nickel ions andan addition agent dissolved insaid solution and capable of imparting to electrodeposits producedtherein high rates of increasing brightness with respect to increasingthickness of deposit, said solution consisting essentially of nickelsulfate equivalent to from 100 to 400 grams of nickel sulfateheptahydrate per liter, nickel chloride equivalent to from 10 to 60grams of nickel chloride hexahydrate per liter, boric acid up to 50grams per liter, and said addition agent being selected from the classconsisting of N,N-ethylene-bis-pyridinium bromide, N,N' trimethylene bispyridinium bromide, N,N' tetramethylene-bis-pyridinium bromide,N,N'-pentamethylene-bis-pyridinium bromide, N,N' decamethylenebis-pyridinium bromide, N,N'-methylene-bis-pyridinium bromide, N,N'-

oxydimethylene-bis-pyridinlum chloride, N,N'-oxyethylenemethylene-bis-pyridinium chloride, N,N' oxydiethylene bispyridinium chloride, N,N'-oxyditrimethylene-bis-pyridinium chloride, N,Nmethylene bis isoquinolinium chloride, N,Noxydimethylene-bis-isoquinolinium chloride, N,N'-oxyethylenemethylene-bis-isoquinolinium chloride,N,N-oxydiethylene-bis-isoquinolinium chloride, N,N'-oxymethylenepyridinium chloride, ethylene isoquinolinium chloride, N,N'-oxydiethylene pyridinium isoquinolinium chloride, propanone 1,3bis-pyridinium chloride, N ,N-oxydipropylene-bis-pyridinium perchlorate,N ,N'- (oxydibutyl) -bis-pyridinium chloride, N,N'-(oxydibutyl)-bis-isoquinolinium chloride, N,N'-(2-butenylene-bispyridinium bromide, N,N'-(2-butenylene)-bis-isoquinolinium bromide, said addition agent beingpresent to the extent of from 0.2 to 0.75 gram per liter.

9. The invention defined in claim 8 wherein said addition agent isN,N'-ethylene-bis-pyridinium bromide.

10. The invention defined in claim 8 wherein said addition agent isN,N-trimethylenebispyridinium bromide.

11. The invention defined in claim 8 wherein said addition agent isN,N'-tetramethylene-bispyridinium bromide.

'12. The invention defined in claim 8 wherein- References Cited in thefile of this patent UNITED STATES PATENTS Name Date Brown July 4, 1950Brown -a Apr. 24, 1951 Number

1. A NICKEL PLATING SOLUTION COMPRISING AN AQUEOUS, ACID SOLUTION OFNICKEL MATERAL SUPPLYING NICKEL IONS AND AN ADDITION AGENT DISSOLVED INSAID SOLUTION AND CAPABLE OF IMPARTING TO ELECTRODEPOSITS PRODUCEDTHEREIN IMPROVED RATES OF INCREASING BRIGHTNESS WITH RESPECT TOINCREASING THICKNESS OF DEPOSIT, SAID SOLUTION CONSISTING ESSENTIALLY OFA COMPOSITION FROM THE CLASS CONSITING OF AQUEOUS SOLUTIONS OF NICKELSULFATE AND AQUEOUS SOLUTIONS OF NICKEL SULFATE AND NICKEL CHLORIDE ANDSAID ADDITION AGENT BEING AT LEAST ONE BIS-PYRIDINIUM COMPOUND OF THEFORMULA